Six months is a short time, and his family may still need time to adjust to the idea
Ican tell that you are really enjoying this relationship and seem to know what the limits are regarding moving in right now. This tells me you are not being “needy”, but rather you are enjoying a mature and respectful friendship. It is such a great feeling to share each other’s company and it is wonderful that you can enjoy your time together.
On the other hand, it may be that his family haven’t had time to adjust to their father being loved by someone else. They seem concerned that this change might threaten their lives. Perhaps he has not told them completely about your relationship or that neither of you have plans to move in with each other? Six months is still a short time from everyone’s perspective, so perhaps they haven’t had time to get used to the idea their father has a new relationship, and they may need more time to adjust.
However, this is their issue and not in your control.
Reduce any expectations to be involved in their family life and you can avoid the stress of pushing it in a direction that doesn’t seem possible right now. By proving to each other and his family, that you are a happy couple, things may change as time goes on. My advice is to enjoy this friendship and the way it makes you feel.